Current portable data terminals have a broad variety of functions such as TV (Television) telephonic function, camera function, Internet function, as well as TV receiving function, FM (Frequency Modulation) radio receiving function, in addition to the basic functions including telephonic function and mail function.
In the housing thereof, however, a smaller size is attained in pursuit of the convenience in handling thereof, and the number of operational keys is restricted. For this reason, a menu screen is used for selection of a block of related functions, from which the intended function is selected. Thus, the menu employs a considerably deep hierarchic structure, wherein a large number of key operations are necessary for selecting the desired function. This causes the problem of complicated operations and time consuming.
In general, selection of each function is allocated to a management number, and the management number may be directly input after depression of the menu key. However, the variety of functions provided therein as described above causes a difficulty in memorizing those of functions other than those used frequently. Eventually, it is necessary to trace the function along the hierarchical structure of the menus.
As to the general function of the telephone call, most of the terminals have a function of displaying the history of outgoing calls and received calls to allow the user to initiate an outgoing call with ease. However, the frequency of use of the terminals as a mere telephone is reduced nowadays. Thus, there is a subject to be solved how to select the desired function and operation with ease from the items of the variety of other functions.
In view of the above, there is a technique in which the operated function histories are sorted and stored in an order of arrangement based on the number of times used, and a stored function histories are called by a dedicated key, whereby a desired function is selected while scrolling by way of up/down keys and determined by depressing an enter key (refer to Patent Publication 1, for example).
However, use of the function history yet necessitates a significant number of key operations including depressions of history calling key, selection by up/down keys and depression of enter key, although the function may be selected by a less number of key operations compared to a first time operation. In addition, the weighting by the number of operations necessitates a plurality of number of key depressions during the scroll using the down key if a function used only once is to be called, and is also inconvenient.
There is another method in which the operation history for setting the function is stored in a memory, similarly to the above technique, and depression of the key for calling the operation history allows three latest operations to be displayed in order (refer to Patent Publication 2, for example).
In this technique, if the received-volume setting is operated, for example, only the received-volume setting is possible upon the calling, and thus there is also a problem that the related function group including the received tone setting, for example, cannot be called.
There is further another method in which a judgment as to whether the storage is performed at selection or at execution is added for a weighting operation during selection of the function, thereby providing an ingenuity that all of the selected ones are not stored (refer to Patent Publication 3, for example). In the case of this technique, the configuration is such that the functions included in the same function group can be selected with ease. More concretely, a direct operation history is selected by the up/down scroll, whereby left/right keys can call the functions in the same function group.
In the case of this technique, there is a problem in that the current cellular phones have a variety of functions which cannot be realized only by guiding the operation, such as input of characters that the user can arbitrarily select or access to the Internet, and that the function and configuration of the up-to-date cellular phones have a complicated transition, whereby only a change of a single setting or stating of a desired function requires a large number of key operations.
As a method for solving the above problems, there is a proposal for a cellular phone in which the values arbitrarily input by the user are accurately reproducible by learning the key operations (refer to Patent Publication 4, for example). In the case of this technique, creation of a mail is registered in the midway thereof as a learned history, whereby another mail can be created until the input of destination and input of the title.
There is another solution in which a single key is allocated to a function which is fixedly assigned to a softkey and to a higher-order function counting the number of started times thereof, and a timer is stared when the softkey is depressed, wherein, if the softkey is depressed twice within a specific period of time, the application function that is set based on the number of starting times is started, whereas if the softkey is depressed once, the function fixedly allocated thereto is started after the specific period of time is elapsed (refer to Patent Publication 5).
Patent Publication 1: JP-2000-261544A
Patent Publication 2: JP-2001-127867A
Patent Publication 3: JP-2002-101179A
Patent Publication 4: JP-2003-244306A
Patent Publication 5: JP-2003-101629A